Effect of enhanced Renilla luciferase and fluorescent protein variants on the Förster distance of Bioluminescence resonance energy transfer (BRET)

► First experimental determination of Förster distance (R0) for enhanced BRET systems. ► Effect of brighter BRET components RLuc2, RLuc8 and Venus was assessed. ► Using brighter BRET components substantially increased (25%) R0 of the BRET1 system. ► Using brighter BRET components marginally increased (2-9%) R0 of the BRET2 system. ► Brighter BRET components improve the different weaknesses of BRET1 and BRET2 systems.